Study on CO<sub>2</sub>-Enhanced Oil Recovery and Storage in Near-Depleted Edge–Bottom Water Reservoirs
The geological storage of carbon dioxide (CO<sub>2</sub>) is a crucial technology for mitigating global temperature rise. Near-depleted edge–bottom water reservoirs are attractive targets for CO<sub>2</sub> storage, as they can not only enhance oil recovery (EOR) but also pro...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-11-01
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| Series: | Journal of Marine Science and Engineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-1312/12/11/2065 |
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| Summary: | The geological storage of carbon dioxide (CO<sub>2</sub>) is a crucial technology for mitigating global temperature rise. Near-depleted edge–bottom water reservoirs are attractive targets for CO<sub>2</sub> storage, as they can not only enhance oil recovery (EOR) but also provide important potential candidates for geological storage. This study investigated CO<sub>2</sub>-enhanced oil recovery and storage for a typical near-depleted edge–bottom water reservoir that had been developed for a long time with a recovery factor of 51.93%. To improve the oil recovery and CO<sub>2</sub> storage, new production scenarios were explored. At the near-depleted stage, by comparing the four different scenarios of water injection, gas injection, water-alternating-gas injection, and bi-directional injection, the highest additional recovery of 3.62% was achieved via the bi-directional injection scenario. Increasing the injection pressure led to a higher gas–oil ratio and liquid production rate. After shifting from the near-depleted to the depleted stage, the most effective approach to improving CO<sub>2</sub> storage capacity was to increase reservoir pressure. At 1.4 times the initial reservoir pressure, the maximum storage capacity was 6.52 × 10<sup>8</sup> m<sup>3</sup>. However, excessive pressure boosting posed potential storage and leakage risks. Therefore, lower injection rates and longer intermittent injections were expected to achieve a larger amount of long-term CO<sub>2</sub> storage. Through the numerical simulation study, a gas injection rate of 80,000 m<sup>3</sup>/day and a schedule of 4–6 years injection with 1 year shut-in were shown to be effective for the case considered. During 31 years of CO<sub>2</sub> injection, the percentage of dissolved CO<sub>2</sub> increased from 5.46% to 6.23% during the near-depleted period, and to 7.76% during the depleted period. This study acts as a guide for the CO<sub>2</sub> geological storage of typical near-depleted edge–bottom water reservoirs. |
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| ISSN: | 2077-1312 |